Removable pressure sensor and extracorporeal circulator provided with removable pressure sensor

Abstract

A removable pressure sensor assembly senses a pressure in an elastically deformable tube conveying blood in an extracorporeal circulator. The assembly includes a main body portion 31 and a pressure measurement element 40 disposed in main body portion 31 . Main body portion 31 has a base portion 32 with a tube mounting recessed portion 34 such that an intermediate part of a tube 11 is removably fitted such that tube 11 is elastically deformed. Pressure measurement element 40 is exposed to tube 11 so that it measures a pressure of blood inside tube 11 . A lid portion 33 holds tube 11 inside tube mounting recessed portion 34 by selectably closing recessed portion 34 of the base portion. Tube mounting recessed portion 34 has a rectangular cross section, and a width L of the rectangular cross section is set to be smaller than an external dimension D of tube 11.

What is claimed is: 
     
       1. A pressure sensor assembly configured to be removably mounted in an intermediate part of an elastically deformable tube for transferring a liquid, the pressure sensor assembly comprising:
 a main body portion; and 
 a pressure measurement element that is disposed in the main body portion; 
 wherein the main body portion comprises:
 a base portion having a tube mounting recessed portion with a cross-sectional width L configured to removably receive the intermediate part of the tube so as to cause the tube to be elastically deformed, wherein the pressure measurement element has a surface bordering the tube mounting recessed portion to cause a pressure of the liquid inside the tube to be transmitted to the pressure measurement element; and 
 a lid portion configured to hold the tube inside the tube mounting recessed portion in a state in which the tube mounting recessed portion of the base portion is closed; 
 
 wherein the width L of a cross section of the tube mounting recessed portion is configured to be smaller than an outside diameter D of the tube, such that L is within a range from L=πD×0.9÷4 to L=πD×1.1÷4; and 
 wherein the tube mounting recessed portion has a substantially square cross section, wherein the pressure measurement element is disposed in a side of the tube mounting recessed portion against which the tube which is elastically deformed when held by the lid portion in the tube mounting recessed portion, wherein a width of the substantially square cross section is set to be smaller than the outside diameter D of the tube so that a substantially flat surface is formed in the tube at the pressure measurement element. 
 
     
     
       2. The removable pressure sensor according to  claim 1 , further comprising:
 a temperature sensor that measures a temperature of an environment in which the tube is positioned; and 
 a control unit that acquires temperature information of the environment from the temperature sensor, acquires the circuit pressure of the liquid inside the tube from the pressure measurement element, and corrects the circuit pressure of the liquid inside the tube measured by the pressure measurement element, in accordance with a value of the temperature. 
 
     
     
       3. The removable pressure sensor according to  claim 1 :
 wherein the lid portion is attached to the base portion in a manner of being selectably opened and closed, and the lid portion holds the tube inside the tube mounting recessed portion in a state in which the lid portion closes the tube mounting recessed portion of the base portion. 
 
     
     
       4. An extracorporeal circulator system for treating blood of a patient, comprising:
 an elastically deformable tube for transferring the blood in extracorporeal circulation; and 
 a removable pressure sensor comprising a main body portion and a pressure measurement element that is disposed in the main body portion; 
 wherein the main body portion comprises:
 a base portion having a tube mounting recessed portion with a cross-sectional width L configured to removably receive an intermediate part of the tube so as to cause the tube to be elastically deformed, wherein the pressure measurement element has a surface bordering the tube mounting recessed portion to cause a pressure of the blood inside the tube to be transmitted to the pressure measurement element; and 
 a lid portion configured to hold the tube inside the tube mounting recessed portion in a state in which the tube mounting recessed portion of the base portion is closed; 
 
 wherein the width L of a cross section of the tube mounting recessed portion is configured to be smaller than an outside diameter D of the tube, such that L is within a range from L=πD×0.9÷4 to L=πD×1.1÷4; and 
 wherein the tube mounting recessed portion has a substantially square cross section, wherein the pressure measurement element is disposed in a side of the tube mounting recessed portion against which the tube which is elastically deformed when held by the lid portion in the tube mounting recessed portion, wherein a width of the substantially square cross section is set to be smaller than the outside diameter D of the tube so that a substantially flat surface is formed in the tube at the pressure measurement element.